Community SSU/Thumb

Revision as of 19:20, 6 December 2017

1 Introduction
2 Installation
3 Uninstallation
4 Disclaimer
5 Changelog

Introduction

Instruction Set Architecture's

The Cortex-A8 SoC we have in our N900 supports several Instruction Set Architecture's (ISA).

These include ARM, Thumb, Thumb2, ThumbEE.

As stock Fremantle, CSSU and all of the software currently in the repositories* come with binaries (i.e. executable files, libraries) compiled using ARM instruction set.

Which is the most powerful and fastest. Every ARM instruction uses exactly 4 bytes of memory.

Note:- *Facebook sharing plugin was compiled by mistake with Thumb2 ISA.

Thumb2

Thumb2 is another instruction set, which has most of the power and speed of ARM ISA, but its instructions could be 2 bytes in length instead of 4 bytes.

According to some research that can be found on internet, using Thumb2 ISA leads to reduction of code size in 30-40% without sacrificing much of the performance (some 2-5% performance decrease).

Memory Usage

We all know that the major performance bottleneck on the N900 is the size of RAM. Constantly swapping pages in and out of memory leads to stutter and lag.

Part of that RAM is used to hold the executable code, so the smaller the code is, the larger part of the RAM will be free to be used for data.

While it is a simplified explanation, you should be able to get the general idea. Smaller code means better code cache usage, less reading from the storage and therefore faster application start times.

With packages that are so far in CSSU-thumb repository, the code size is reduced by approximately 35MiB.

As more packages are included, more RAM and storage space will be regained in the future.

The Catch

The SoC revision inside our N900 has silicon erratas or put simply bugs in the hardware. These render Thumb2 compiled binaries unstable if no countermeasures are taken.

A system without fixes for the erratas, that tries to run Thumb2 binaries, crashes randomly, not only in Thumb2 compiled executables/libraries, but in ordinary ARM ones too.

The Countermeasures

There are two erratas that must be worked around on N900 in order for Thumb2 compiled binaries to not lead to system instability.

These are ARM errata 430973 and ARM errata 657417

ARM errata 430973

This is worked around in the kernel by clearing a special type of cache (Branch Target Buffer) inside the chip on every context switch made by the CPU.

In theory that slows down the system. I didn't make any benchmarks, but from current testing there is no visible performance loss.

A special call to Secure Monitor (that is a piece of ROM in our SoC programmed by Texas Instruments during chip manufacture) is needed to properly enable the workaround.

Therefore CSSU Thumb requires a kernel which has the workaround. This is provided in Kernel-CSSU or the latest version of Kernel Power

ARM errata 657417

This is worked around in the in linker, all binaries in the CSSU Thumb repository are compiled using Linaro gcc 4.7.2 and binutils 2.22.

Information on how to setup the CSSU-thumb toolchain (gcc4.7.2-linaro) in scratchbox is linked below

CSSU Thumb Toolchain Setup

Installation

Make sure Nokia and Extras catalogues are enabled in application manager.

Using MicroB on your N900 click on the link below.

CSSU Thumb Install

The installation process is the same as other CSSU Flavours

Community_SSU#Installation

CSSU-Thumb is based on CSSU-Testing flavor.

If you have kernel-power v51r1 or above, no custom kernel will be installed, as needed errata workaround is now included in kernel-power.

Uninstallation

There is no way to uninstall, i.e. the same rules apply as for the other CSSU flavors. The only way to rollback without messing with apt-get is to Reflash. Or you can downgrade all of the packages manually using apt-get.

Disclaimer

This is still in development stage and while so far there are no known issues, I will take no responsibility for any damage and/or data loss caused by using CSSU-thumb repository. It is highly unlikely to happen, but be prepared to reflash if something goes south. Make a full backup of your data and settings before installing.

Changelog

Detailed cssu-thumb changelog on github - most up to date. Wiki is updated sparingly..

15.06.2012 - 21.2011.38-1Tmaemo4-thumb7

Qt libraries moved back to /opt
added new packages: qt-mobility, clutter, libhildonfm, osso-gnome-vfs2

16.06.2012 - 21.2011.38-1Tmaemo4-thumb9

added new packages: libalarm2, alarmd, libxml2

20.06.2012 - 21.2011.38-1Tmaemo4-thumb10

added new packages: xserver-xomap, xserver-xorg-core
fixed a bug in the kernel : Clear the IT state when invoking a Thumb-2 signal handler http://git.et.redhat.com/?p=kernel-k...62e8de4406ac7e

19.07.2012 - 21.2011.38-1Tmaemo4-thumb11

added new packages: microb-engine

27.07.2012 - 21.2011.38-1Tmaemo4-thumb12

toolchain upgrade to gcc 4.7.2
microb-engine - fixed HTTPS TLS error
Qt libraries rebuild with the new toolchain

29.07.2012 - 21.2011.38-1Tmaemo4-thumb13

kernel upgraded

01.08.2012 - 21.2011.38-1Tmaemo4-thumb14

fixed a bug in tinymail

04.09.2012 - 21.2011.38-1Tmaemo4-thumb16

microb-engine source code was missing some stuff from maemo.org, rebased.
add libcurl3 (7.26.0-1maemo1+0cssu1-thumb1) - fix for Facebook widget, photo uploader and MfE IPv6 problems

15.09.2012 - 21.2011.38-1Tmaemo5.1+thumb0

rebased on top of 21.2011.38-1Tmaemo5.1 CSSU-testing
changed versioning scheme
added thumb-compiled camera-ui, alarmd, hildon-application-manager, apt, modest

Because of the versioning scheme change you should follow the instructions here if upgrading from 21.2011.38-1Tmaemo4-thumb16 or older version.

23.09.2012 - 21.2011.38-1Tmaemo5.1+thumb1

added missing dependency (system-services (>= 0.3.8-68+0cssu0))
Thumb2 compiled dosfstools and openssl

25.09.2012 - 21.2011.38-1Tmaemo5.1+thumb2

Thumb2 compiled gdigicam and gst-plugins-bad

03.10.2012 - 21.2011.38-1Tmaemo5.1+thumb3

Thumb2 compiled sqlite3, gstreamer, gst-plugins-base, gst-plugins-good

03.11.2012 - 21.2011.38-1Tmaemo5.1+thumb4

Thumb2 compiled db4.2, pulseaudio, calendar-backend, evolution-data-server

26.12.2012 - 21.2011.38-1Tmaemo7.1+thumb0

packages updated to latest CSSU-testing(21.2011.38-1Tmaemo7.1)
Thumb2 compiled obexd, gnome-vfs-filechooser-backend, ke-recv, libmatchbox2, rtcom-eventlogger-async

06.01.2013 - 21.2011.38-1Tmaemo7.1+thumb1

Thumb2 compiled pango, freetype, libpng, zlib, libxml2
NEON-optimized upstream versions of libpng (~30% faster) and zlib (~8% faster decompression, ~18% faster compression)
libxml2 recompiled against latest zlib

07.01.2013 - 21.2011.38-1Tmaemo7.2+thumb0

packages updated to latest CSSU-testing(21.2011.38-1Tmaemo7.2) - blacklist fraudulent TURKTRUST intermediate certificates

07.04.2013 - 21.2011.38-1Tmaemo7.2+thumb1

pixman upgraded to upstream version 0.29
build microb against system libpng and zlib
pulseaudio, qt and hildon-desktop upgraded to latest CSSU versions on gitorious

15.07.2013 - 21.2011.38-1Tmaemo8.2+thumb1

packages updated to latest CSSU-testing(21.2011.38-1Tmaemo8.2)
thumb-compile tracker, hildon, hildon-thumbnailer

3.11.2013 - 21.2011.38-1Tmaemo8.3+thumb1

osso-systemui-alarm: Fix nsv_sv_play_event call
maemo-security-certman: Change VeriSign certificate order, fixes supl.nokia.com not working

12.11.2013 - 21.2011.38-1Tmaemo8.3+thumb2

upgrade glib to 2.24.1
upgrade pulseaudio to 0.9.15-1maemo44+0m5+0cssu5
Thumb2 compile alsa-lib, glib, pulseaudio, telepathy-glib, telepathy-gabble and osso-pdf-viewer

24.11.2013 - 21.2011.38-1Tmaemo8.3+thumb3

upgrade hildon-desktop to 1:2.2.153-2+thumb0
Thumb2 compile cairo, libx11, libxfont

30.12.2013 - 21.2011.38-1Tmaemo9+thumb1

clock-ui: Open source rewrite of the nokia clock-ui, thanks to Adekker (ade)
camera-ui: Added Fallback to DCIM if NOKIA_CAMERA_DIR or NOKIA_MMC_CAMERA_DIR environment variable is not defined

Removed some GLIB Warning messages when changing profile

dosfstools: Fixed install paths, data will be installed to /usr/share instead of /share
e2fsprogs: Updated to upstream 1.42.5, fixes fsck for ext* filesystems
glibc: Enabled kernel implementations of epoll, ppoll and pselect
fmtx-middleware: Fm TX now keeps running when headphones/usb is plugged in
gtkfilesystemmemory: Moved development files to osso-memory-backend-dev, frees rootfs space
hildon-welcome: Fixed not running when /proc/bootreason is missing (ie. an upstream kernel is used)
initrd-progs: Open source replacement with new feature -G which prints block data to stdout
ke-recv-extra: Fixed 100% Cpu use on 3.x kernels
libcpaboutcssu: dpkg-query instead of shell hack, added luf
maemo-tvout-control: Moved maemo-applet-tvout back into libs section, fixes control panel entry missing
modest: Moved recursive imap operations into glib main loop, fixes 100% Cpu / freeze on imap sync
modest-l10n: Added english string for mcen_fi_advsetup_update_all_folders
osso-af-utils: Replaced call to getbootstate with read of /var/lib/dsme/saved_state,

fixed boot when /proc/bootreason is missing

osso-calculator: Added support for top_application dbus call
osso-systemui-tklock: Fixed bug #12701: Ball is moving when touching anywhere along the bar-slide
profiled: Open source replacement version from Nokia (harmattan/nemo)
qt4-x11-maemo: Added MeeGo libs, change compiler flags
status-area-applet-battery: Open source replacement which works with BME hal, bq27200 hal, rx51-battery hal
upstart: Enabled auto fsck on boot, added support for swap_opts in /etc/default/mount-opts
Thumb2 compile clock-ui, e2fsprogs, gtkfilesystemmemory, ke-recv-extra, osso-af-utils, profiled

12.01.2014 - 21.2011.38-1Tmaemo9.1+thumb0

fmtx-middleware: revert to 0.62, fixes US model issues

__________________

Retrieved from "http://wiki.maemo.org/Community_SSU/Thumb"

@@ Line 84: / Line 84: @@
 =Changelog=
+[https://github.com/community-ssu/mp-fremantle-community-pr/blob/thumb-testing/debian/changelog Detailed cssu-thumb changelog on github] - most up to date. Wiki is updated sparingly..
 ===15.06.2012 - 21.2011.38-1Tmaemo4-thumb7===

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